[Objective] The distribution of soil aggregates and the characteristics of organic carbon content were analyzed to determine the influence of biological crust on slope stability and nutrient retention in order to provide a reference and guidance for the application of biological crusts in slope restoration engineering.[Methods] Taking a restoration slope with vegetation concrete substrates as an example, the soil dry screening method and the soil wet screening method were used to study aggregates in the crust (0-2 cm) and subsurface layer (2-7 cm) and organic carbon characteristics of crust-covered and non-crust-covered slope soil.[Results] ① The presence of biological crusts significantly affected the distribution of soil aggregates, mechanical stability, and R_0.25 content. Compared with the check treatment (CK, no crust-covered slope), the stability index of the crust covering layer increased by 27.42%-33.51% (MWD) and 21.66%-28.88% (GMD), and the content of large aggregates (R_0.25) increased by 10.68%. Moss crust had the most significant impact. ② Soil aggregate particle size of different crust types measured by the wet sieving method were mainly>0.25 mm. The water stability parameters MWD, GMD, and R_0.25 of the crust-covered slopes were between 1.93 and 5.33 mm, 0.85 and 3.16 mm, and 70.97% and 87.50%, with moss-covered slopes having the largest values. The D_d values were between 2.48 and 2.74, with the smallest values observed for moss-covered slopes. The water stability of aggregates was best for moss-covered slopes and worst for bare slopes. ③ The presence of crust promoted the accumulation of organic carbon in the soil, and the organic carbon content was more than twice that of the CK treatment. The effect on the organic carbon level for the surface soil was obvious, and the effect for the subsurface soil layer was low. ④ There was a significant positive correlation between soil organic carbon content and soil water stability parameters MWD, GMD, and R_0.25 (p<0.05). The level of organic carbon and the stability of aggregates were closely related and affected each other. Increasing organic carbon level played an important role in increasing aggregate stability.[Conclusion] The existence of a biological crust increases aggregate stability and organic carbon accumulation of repaired slopes. The crust has a certain effect on the stability of the ecologically repaired slope and on nutrient fixation. The strength of different crust types varies, with moss and mixed crusts having the best soil fixation and carbon sequestration effects.